Method of and apparatus for placing pavement slabs and the like



C. JACKSON April 11, 1944.

METHOD 0F AND APARATUS FOR PLACING PAVEMENT SLABS AND THE LIKE Filed July 25, 1941 new 4 L l. m.

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INV ENT OR. WW/L Jia/fsm Patented Apr. 11, 1944 fu-N'ITED STATrllSV PATENT OFF-CE METHOD OFFAND APPARATUS FOR PLACING PAVEMENTSLABS AND THE LIKE Colvvill Jackson, Ludington, Mich.

1vApplicationLla'uly 23, 1941,'Serial No. 403,667

` s claims. (o1. iii- 24) lThis `'invention `relates to improvements in method of -'and apparatus for placing pavement rslabs and thelike.v I v The main'object of this `invention `is to pro- -vide va method of placing highway or pavement slabs which enables the rapid' placement of harsh `mixtu`res of Vconcrete or mixtures having no- 4`slump water content or mixturesbeing of such lowwater content as to be diicult to spread and Vtdplace ina lsatisfar'ztorymanner.

ivIn the accompanying drawing, I illustrate an `apparatus by means of whichqny method may vvbepracticed and illustrating the steps thereof,

parts of the apparatus being snowngin conven- -tional form.

In the'accompanying drawing, I represents a side form, 2 the concrete 4mixture to be treated bythe method and 3 the concrete after treat- -ment in accordance with the method.

The apparatus illustrated comprises a carriage "designated generally by the numeral 3| having rcarrying and driving wheels 4 adaptedto travel on the forms I which constitute tracks or rails,

only one'form being illustrated. The engine, in I dicated conventionallyat 5, is commonlyadapted" to drive the carriage as well as to furnishpower `for vthe screed constituting a partfof the apparatus illustrated.

The screed 6 is of` the typeadapted to .be-re-v, ciprocated transversely o f the path of forward travel, b eing driven from the crank 'I connected to the screed by the pitman orconnecting rod 8.

'I'he means for advancinvg'the screed are4 not illustrated.

The screed is provided with a vibrating unit SlA ,preferably in the form of an electric motor having a rotor with an unbalancing weight indicated by dotted lines'at IIJ.

a spiralor screw type of spreader II which-is designed Vto be reverselydriven, the spreader beirlgfcarri'ed by the hangers I2 pivoted at I3 and `vertically adjustedbi7 means'of the screw I4 having anut I5 associated "therewith and provided l 'with a hand wheel. The spreader is driven from an engine I6 through suitable driving connec- Y"tions indicated generally by the numeral I'I designedto reversibly drive the spreader. The reversible transmission yand 'the means for manu'ally 'controlling'therefor arenot illustrated. v -At the rear of the'spreader isavbratory memljer I8, `this being of substantialwidth and adapted 'to support asubstantial mass of material ytreated' or being placed'while it is acted upon by lthespreader. Thisvibratory 'member is sup- At the forward end of thec'arriage, I provide `tl0 ported by the flexible hangers I9 carried by arms 20 von the rock shaft 2l, this rockshaft being provided with an arm 22 having a nut 23 journaled thereon to coact with the'screw 24 provided with a hand wheel 25 so that the vibratory member may be raised and lowered, the -vibratory member acting as a combined vibrator and strike-off.

The vibratory member I8 is provided fwith 'a vibrating motor 26 having a rotor 21 which is provided with an unbalanced weight 28 so that lthe rvibratory member is vibrated at high frea narrow reservoir 30 between the face: of the screed and the vibratory member '29.' vThievibratory member is provided with a vibrating unit 3I preferably of the same' character asithe Vibratory units 29 and 26 comprising an electric motor, the rotor 32 of which is provided with an unbalan'cing weight. The vibratory member 29 is supported for vertical adjustment by the hangers 33.

As the `machine is advanced, the reservoir space l3d accumulates a quantity of the treated material indicated at 34, this commonly, being the "nes of the material which builds up therein tosuch` an extent v.that it is gradually fed down tothe screed, insuring a highly desirable surface well suppliedwith mortar.

"rhenvibratory member `2e is adaptedwto supporta substantial mass of material as it is ad- '1/anced; it being advanced at high frequency serves to supplement the vibratory member I8 in "reducing the material to the desired condition for most effective screeding and placement, eliminating voids and providing a Very compact placement thereof.v

By this method, the concrete may be dumped between lAthe forms in which conditiont has a high percentage of voids, andasthe method is designed for placement of harsh or concrete mixtures or mixtures of low water content it 4is very `'dificult to propel either manually ormechanically. However, by subjecting it `to"'thevvib'ra 'tiche lvduring tl-ie V'spreading `opertion, the voids are very rapidly reduced and the material in which the spreader operates becomes workable and uid-like. This operation in itself deposits the concrete in a state of high density and with relatively few voids. By vibrating the mixture during this spreading operation, the spreading is accelerated which I have demonstrated increases the spreading capacity in the neighborhood of fifty percent. The material is struck off properly to be acted upon in the succeeding step where it is subjected to the combined action of the second vibrator and screed. The second vibrator acts as a still further vibrator and also acts with the screed to provide the reservoir of surfacing material which is uniformly fed to the screed as is required in order to provide the desirable surface. The resulting placed concrete is very dense and compact and requires but a minimum of time before it may be walked upon or even a truck may be driven thereon without appreciable damage. It is of course preferable vthat the concreteset before it is open to trafcl .By mymethod, the speed with which concrete may be placed is very greatly increased with ree v`sulting economy and practically no manual labor is required in the spreading.

Having thus described mypinvention, what I claim as new and desire to secure by Letters Patent is:

v1. The method of placing concrete mixtures of low water content in pavements and the like, comprising the steps performed successively and continuously of vibrating at high frequency a, mass of material to .be placed while spreading the material in the zone of vibration thereof transversely ofthepath of the surface to be paved, thereafter striking off the thus placed material rearwardly of said zone while again vibrating said material adjacent the strike-oli zone at high frequency, immediately thereafter screedingthe surface thus laid while accumulating a quantity of the last vibrated material in a fluidlike consistency. in a space intermediate the [screeding zone and said strike-off zone of v1- bation, and advancing said accumulated material while screeding, whereby the same is gradually fed'downwardly by hydrostatic head in adv vance of thev screeding zone.

2. The method' of placing concrete mixtures of low water content in pavements and the like, comprising the vsteps performed successively and continuously of vibrating at high frequency and forwardly distributing a mass of material to -be placed, thereafter striking off the thus distributed material rearwardly of said vibration zone while vibrating at high frequency adjacent the strikeeoff zone, immediately thereafter screeding the surface thus laid while accumulating a quantity of the last Vibrated material in a fluid-like consistency in a space intermediate the screeding zone and said vibratory strike-off zone, and advancing said accumulated material while screeding, whereby the same is gradually fed downwardly by hydrostatic head in'advance of the screeding zone. n

The methodVA of placing concretey mixtures of low water content in pavements and the like,

comprisingthe steps performed successively and continuously of rearwardly supporting and vibrating at high frequency a. mass of material to. be placed while spreading the material transversely in the zone of vibration thereof, screeding the surface thus -laid while accumulating a quantity of the material in a fluid-like consistency in a space intermediate .the lscreeding zone and said zone of vibration, and advancing said accumulated material, whereby the same is gradually fed downwardly by hydrostatic head in advance of the screeding zone.

4. The method of placing concrete mixtures of low water content in pavements and the like, comprising the steps performed successively and continuously of supporting a mass of material to be placed while vibrating said mass at high frequency, thereafter striking oi the material rearwardly of said vibration zone while likewise vibrating at high frequency at the strike-off zone, thereafter screeding the surface thus laid while accumulating and advancing a quantity of the last vibrated material in a uid-like consistency in a space intermediate the screeding zone and said strike-off zone, whereby the same is gradually fed downwardly by hydrostatic head in advance of the screeding zone.

5. An apparatus for placing low water content concrete mixtures in pavements and the like, comprising aforwardly advanceable carriage; a vibratory member extending transverse the carriage and the path of advancementthereof, said vibratory member being vengageable with a mass of concrete to be laid, means .for vibrating said member at high frequency, a spreader disposed in advance of said vibratory member for spreading engagement in the mass of material vibrated by the latter in the zone of vibration of said mass, a vibratory strike-off member positioned rearwardly of said rst named member, means for vibrating said vibratory strike-off member, and a screed disposed immediately to the rearof said vibratory strike-off member to provide a narrow reservoir or hopper therebetween, said'vibratory strike-off member Vibrating a quantity of the material previously distributed by said rst member and spreader and said reservoir accumulating a mass of fines of said material in a semi- 'fluid consistency adapted to iiow downwardly from the reservoir in advance of the screed, said spreader, vibratory members and screed being supported on said carriage for advancement therewith in the aforesaid relation to one another.

6. An apparatus'for placing low watercontent concrete mixtures in pavements and the-like, comprising a forwardly advanceable carriage, a vibratory strike-off member extending transverse the carriage andthe pathv of advancement thereof, said vibratory member being engage'able with a mass of concrete to be laid, means for vibrating said member at high frequency, a spreader disposed in advance of said vibratory member for spreading engagement in Vthe'mass of material, and a screed disposed immediatelyto the rear of said vibratory member to provide a narrow vreservoir or h'opper therebetween, said vibratory member' vibrating a quantity of vthe material previously distributed by `said spreader and said reservoir accumulating a mass of'nes of said material in a semi-iiuid consistency adapted to flow downwardly from the reservoir inv advance of the screed, said spreader, vibratory member and screed being supported on said carriage for advancement therewith in they aforesaid relation to one another.

7. An apparatus lforplacing lowV water content concrete mixtures .in pavements and the like comprising. a carriage, a vibratory member veX- tending transversely ofthe carriage-andy of the path of advancement thereof for advancement therewith,"said vibratory member beine adapted to rearwardly support a substantial mass of concrete mixture in iront thereof as the vibratory member is advanced against a mass of concrete mixture, means for vibrating said vibratory member and through it the concrete mixture so supported and for a substantial distance in ad- Vance of the vibratory member and rendering it fluid or semi-fluid as the carriage is advanced, and a spreader supported on said carriage in front of said vibratory member for advancement therewith and in the zone of the material supported and vibrated by the vibratory member and rendered fluid by the vibrations thereof -for spreading the said vibrated material longitudinally of the vibratory member.

8. An apparatus for placing low water content concrete mixtures in pavements and the like comprising a carriage, a screed member mounted on and extending transversely of the path of travel of the carriage and adapted to rearwardly support a substantial mass of the concrete mixture in front thereof as the screed member is advanced against the concrete mixture, means for vibrating the concrete mixture so supported and rendering it fluid or Vsemi-fluid in advance of the screed member, anda spreader disposed in advance of the screed member for advancement therewith and in the zone of the concrete mixture supported and vibrated by the screed member which has been rendered fluid or semi-fluid and acting to spread the said vibrated material longitudinally of the screed member for screeding action thereby.

CORWILL JACKSON. 

